AbstractThe oldest method for the managing of the illness is the use of medicinal plants. The use of herbal products as the first choice in self-treatment of minor conditions continues to expand rapidly across Iran. This makes the safety of herbal products an important public health issue.Pesticides are used widely in agriculture to increase the production by controlling the harmful insects and disease vectors, however it has some hazards on biological system of human especially children. The present study evaluated the residual amount of organophosphorus pesticides (Diazinon and Chlorpyrifos) in children herbal medicines available in the Iranian market. Five children herbal medicine liquid dosage forms were purchased from pharmacy store. They were extracted with SPME (Solid Phase Microextraction) using the PDMS-DVB fibre. Then the extracts were injected into a GC. The gas chromatograph was Younglin model YL 6100 equipped with a flame ionization detector. The column was Technokroma 60 m length, 0.53 mm internal diameter and 1.25µm film coated. Standard curves showed the presence and quantity of diazinon and chlorpyrifos. Some herbal medicines had trace amounts of chlorpyrifos and diazinon. Based on European pharmacopeia, threshold limits of chlorpyrifos and diazinon residues for medicinal plant materials are 0.2 and 0.5 mg/kg respectively. Our analysis results showed that residue limits of these two pesticides in five children herbal medicines are ignorable. Key Word: Diazinon, Chlorpyrifos, SPME (Solid-Phase Microextraction), GC-FID, Children herbal medicine